The invention relates to a portable therapeutic device, one especially adapted to be worn by a user while therapeutic heat is being applied to a portion of the user's body.
There have been provisions for application of heat to an individual's body utilizing heat sources worn by the user, in the past. Such devices have usually been for the purposes of keeping the user warm, such as shown in U.S. Pat. Nos. 3,079,486 and 3,084,241. However there have been suggestions in the past (see co-pending application Ser. No. 972,346 filed Dec. 22, 1978, now U.S. Pat. No. 4,201,218) for applying heat to body portions for therapeutic purposes. Heretofore, however, proposed devices have had a number of problems associated therewith that limited their applicability for applying therapeutic heat to body portions. In particular, prior proposed devices have been incapable of providing sufficient amounts of heat over sufficient periods of time to be really useful for therapeutic purposes. Also, proposed devices have incorporated the power sources directly with the heat applying structures, making the mounting thereof on body portions cumbersome, and interfering with normal physical activities. Other problems inherent in prior proposed devices include costs of manufacture, difficulties of manufacture, or lack of adaptability.
According to the present invention a portable therapeutic heating device is provided which overcomes most of the drawbacks inherent in the prior art proposals. A device according to the present invention is capable of heating a body portion so that the skin temperature reaches 102.degree.-108.degree. F., and is capable of supplying heat for periods of about four to five hours, long enough to have significant therapeutic benefits. The device according to the invention is utilized so that it does not interfere with normal activity, and can be worn by the user while performing most normal functions. The inventive device can be constructed from off-the-shelf components, and utilizes batteries that are readily rechargeable. In order to protect the batteries, an indicator is provided for indicating when the voltage of a battery utilized reaches a predetermined value below the rated value of the battery. The inventive device is also simple and easy to construct and utilize, with minimum chances of damage and with maximum adaptability.
A portable therapeutic device according to the invention comprises two main components, a battery pack adapted to receive at least one battery therein, and means for applying heat to a localized portion of the body so that the skin temperature of that body portion reaches about 102.degree.-108.degree. F., said means comprising a flexible heating unit having a plurality of distinct sets of electrical resistance heating elements associated therewith. Electrical interconnection means are provided for operatively interconnecting the battery received by the battery pack to the heat applying means electric resistance heating element sets. The electrical interconnection means preferably comprises a flexible flat tape providing the only connection between the battery pack and the heating unit, such means being dimensioned so that the heat applying means may be positioned on body parts remote from the center of gravity of the body while the battery pack is mounted at the body center of gravity. Means are provided for providing ready attachment of the battery pack to the approximate center of gravity of one's body, and means are provided for providing ready attachment of the heat applying means to a body part in therapeutic heat applicating association therewith. Selector switch means are operatively associated with the electrical connection means and attached to the battery pack for selecting which of the sets of electric resistance heating elements will be energized by a battery received by the battery pack to thereby vary the amount of heat applied by the heating means to a body part.
The battery pack preferably is adapted to receive at least one rechargeable battery, preferably two "D" 2-volt, in series, lead-acid rechargeable batteries, having a combined voltage of four volts. The device further comprises charging circuitry means and a charger plug receptacle mounted on the battery pack for receipt of a charger plug for effecting recharging of a rechargeable battery received by the battery pack, and circuitry means are provided operatively associated with the electrical interconnection means and attached to the battery pack for indicating when the voltage of the rechargeable battery or batteries received by the battery pack reaches a predetermined value below the rated value of the battery or batteries.
The battery pack includes a casing having a top surface and side surfaces, and a cutout is defined in the casing at the interface of the top surface and a side surface with the selector switch mounted in the cutout. Another cutout can be provided for a plug for providing plugging of the electrical interconnection means into the battery pack, and another cutout for the recharger plug. A printed circuit board is provided under the casing cover and completely covering the battery or batteries, all of the electrical components being mounted on the printed circuit board.
The heat applying means may comprise a wide variety of conventional heat applicator structures which are particularly constructed for therapeutic heat application. For instance, the heat applying means may comprise a silicone rubber flexible heating unit with the electric resistance heating elements comprising multi-stranded nickel alloy resistance wire elements. Three distinct sets of electric resistance heating elements may be provided, each set when switched in causing the raising of a larger area to a lower temperature than without such sets switched in. Alternatively the heat applying means may comprise an etched foil heating unit, or the like.
It is the primary object of the present invention to provide an effective portable therapeutic device. This and other objects of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.